Field of the Invention
The present disclosure relates to an image pickup apparatus and an image pickup method.
Description of the Related Art
In recent years, more and more solid-state image pickup elements that are used in image pickup apparatus such as digital still cameras and digital video cameras are given multiple functions.
A technology related to a solid-state image pickup element capable of pupil-division focus detection is described in Japanese Patent Application Laid-Open No. 2001-083407. In Japanese Patent Application Laid-Open No. 2001-083407, two photodiodes are provided for one pixel associated with one microlens. The photodiodes therefore receive light fluxes that have passed through different areas of an exit pupil of a photographic lens. The focal point may be detected by comparing signals that are output separately from the two photodiodes with each other. The signals from the two photodiodes are added as an added signal, based on which a photographed image may be obtained.
There is described in Japanese Patent Application Laid-Open No. 2004-222154 how a black level correction value is obtained for a slave photosensitive pixel by multiplying the black level correction value of its master photosensitive pixel by an area ratio that is the ratio of the cell area of the master photosensitive pixel and the cell area of the slave photosensitive pixel.
However, the black level cannot always be corrected properly in image pickup apparatus of the related art.